Multi-speed planetary transmission

ABSTRACT

A multi-speed transmission including a plurality of planetary gearsets and a plurality of selective couplers to achieve at least nine forward speed ratios is disclosed. The plurality of planetary gearsets may include a first planetary gearset, a second planetary gearset, a third planetary gearset, and a fourth planetary gearset. The plurality of selective couplers may include a number of clutches and a number of brakes. The multi-speed transmission may have four planetary gearsets and six selective couplers. The six selective couplers may include three clutches and three brakes or four clutches and two brakes.

RELATED APPLICATION

This application is a continuation application of U.S. patent Ser. No.15/278,951, filed Sep. 28, 2016, titled MULTI-SPEED PLANETARYTRANSMISSION, the entire disclosure of which is expressly incorporatedby reference herein.

FIELD OF THE DISCLOSURE

The present disclosure relates to a multi-speed transmission and inparticular to a multi-speed transmission including a plurality ofplanetary gearsets and a plurality of selective couplers to achieve atleast nine forward speed ratios and at least one reverse speed ratio.

BACKGROUND OF THE DISCLOSURE

Multi-speed transmissions use a plurality of planetary gearsets,selective couplers, interconnectors, and additional elements to achievea plurality of forward and reverse speed ratios. Exemplary multi-speedtransmissions are disclosed in US Published Patent Application No.2016/0047440, Ser. No. 14/457,592, titled MULTI-SPEED TRANSMISSION,filed Aug. 12, 2014, the entire disclosure of which is expresslyincorporated by reference herein.

SUMMARY

The present disclosure provides a multi-speed transmission including aplurality of planetary gearsets and a plurality of selective couplers toachieve at least nine forward speed ratios. The plurality of planetarygearsets may include a first planetary gearset, a second planetarygearset, a third planetary gearset, and a fourth planetary gearset. Theplurality of selective couplers may include a number of clutches and anumber of brakes. In one example, the present disclosure provides amulti-speed transmission having four planetary gearsets and sixselective couplers. The six selective couplers may include threeclutches and three brakes or four clutches and two brakes.

In some instances throughout this disclosure and in the claims, numericterminology, such as first, second, third, and fourth, is used inreference to various gearsets, gears, gearset components,interconnectors, selective couplers, and other components. Such use isnot intended to denote an ordering of the components. Rather, numericterminology is used to assist the reader in identifying the componentbeing referenced and should not be narrowly interpreted as providing aspecific order of components. For example, a first planetary gearsetidentified in the drawings may support any one of the plurality ofplanetary gearsets recited in the claims, including the first planetarygearset, the second planetary gearset, the third planetary gearset, andthe fourth planetary gearset, depending on the language of the claims.

According to an exemplary embodiment of the present disclosure, atransmission is provided. The transmission comprising at least onestationary member; an input member; a plurality of planetary gearsetsoperatively coupled to the input member; a plurality of selectivecouplers operatively coupled to the plurality of planetary gearsets; andan output member operatively coupled to the input member through theplurality of planetary gearsets. Each planetary gearset of the pluralityof planetary gearsets includes a sun gear, a plurality of planet gearsoperatively coupled to the sun gear, a planet carrier operativelycoupled to the plurality of planet gears, and a ring gear operativelycoupled to the plurality of planet gears. The plurality of planetarygearsets includes a first planetary gearset, a second planetary gearset,a third planetary gearset, and a fourth planetary gearset. Each of theplurality of selective couplers has an engaged configuration and adisengaged configuration. The plurality of selective couplers includes afirst number of clutches and a second number of brakes, the first numberbeing equal to or greater than the second number. The output member isfixedly coupled to the plurality of planetary gearsets through a firstring gear of the plurality of planetary gearsets and through a firstplanet carrier of the plurality of planetary gearsets. The input memberis fixedly coupled to the plurality of planetary gearsets through afirst sun gear of the plurality of planetary gearsets and through asecond sun gear of the plurality of planetary gearsets. The transmissionfurther comprises an interconnector which fixedly couples a second ringgear of a first subset of the plurality of planetary gearsets to a thirdsun gear of a second subset of the plurality of planetary gearsets. Thefirst subset of the plurality of planetary gearsets includes the firstplanetary gearset and the second planetary gearset. The second subset ofthe plurality of planetary gearsets includes the third planetary gearsetand the fourth planetary gearset.

According to another exemplary embodiment of the present disclosure, atransmission is provided. The transmission comprising at least onestationary member; an input member rotatable relative to the at leastone stationary member; a plurality of planetary gearsets operativelycoupled to the input member; and an output member operatively coupled tothe input member through the plurality of planetary gearsets androtatable relative to the at least one stationary member. Each of theplurality of planetary gearsets includes a first gearset component, asecond gearset component, and a third gearset component. The pluralityof planetary gearsets includes a first planetary gearset, a secondplanetary gearset, a third planetary gearset, and a fourth planetarygearset. The output member is fixedly coupled to the second gearsetcomponent of the fourth planetary gearset and to the third gearsetcomponent of the third planetary gearset. The transmission furthercomprising a first interconnector which fixedly couples the thirdgearset component of the first planetary gearset to the second gearsetcomponent of the second planetary gearset; a second interconnector whichfixedly couples the third gearset component of the second planetarygearset to the first gearset component of the third planetary gearset;and a plurality of selective couplers. The plurality of selectivecouplers includes a first selective coupler which, when engaged, fixedlycouples the second gearset component of the first planetary gearset tothe at least one stationary member; a second selective coupler which,when engaged, fixedly couples the first gearset component of the secondplanetary gearset to the at least one stationary member; a thirdselective coupler which, when engaged, fixedly couples the secondgearset component of the third planetary gearset to the first gearsetcomponent of the first planetary gearset and the first gearset componentof the fourth planetary gearset; a fourth selective coupler which, whenengaged, fixedly couples the second gearset component of the firstplanetary gearset to the first gearset component of the third planetarygearset and the third gearset component of the second planetary gearset;a fifth selective coupler which, when engaged, fixedly couples the thirdgearset component of the fourth planetary gearset to the second gearsetcomponent of the third planetary gearset; and a sixth selective couplerwhich, when engaged, fixedly couples the first gearset component of thesecond planetary gearset to the second gearset component of the thirdplanetary gearset.

According to yet another exemplary embodiment of the present disclosure,a transmission is provided. The transmission comprising at least onestationary member; an input member rotatable relative to the at leastone stationary member; a plurality of planetary gearsets operativelycoupled to the input member; and an output member operatively coupled tothe input member through the plurality of planetary gearsets androtatable relative to the at least one stationary member. Each of theplurality of planetary gearsets includes a first gearset component, asecond gearset component, and a third gearset component. The pluralityof planetary gearsets includes a first planetary gearset, a secondplanetary gearset, a third planetary gearset, and a fourth planetarygearset. The output member is fixedly coupled to the second gearsetcomponent of the fourth planetary gearset and to the third gearsetcomponent of the third planetary gearset. The transmission furthercomprising a first interconnector which fixedly couples the thirdgearset component of the first planetary gearset to the second gearsetcomponent of the second planetary gearset; a second interconnector whichfixedly couples the third gearset component of the second planetarygearset to the first gearset component of the third planetary gearset;and a plurality of selective couplers. The plurality of selectivecouplers includes a first selective coupler which, when engaged, fixedlycouples the second gearset component of the first planetary gearset tothe at least one stationary member; a second selective coupler which,when engaged, fixedly couples the first gearset component of the secondplanetary gearset to the at least one stationary member; a thirdselective coupler which, when engaged, fixedly couples the secondgearset component of the third planetary gearset to the first gearsetcomponent of the first planetary gearset and the first gearset componentof the fourth planetary gearset; a fourth selective coupler which, whenengaged, fixedly couples the second gearset component of the firstplanetary gearset to the first gearset component of the third planetarygearset and the third gearset component of the second planetary gearset;a fifth selective coupler which, when engaged, fixedly couples the thirdgearset component of the fourth planetary gearset to the second gearsetcomponent of the third planetary gearset; and a sixth selective couplerwhich, when engaged, fixedly couples the second gearset component of thethird planetary gearset to the at least one stationary member.

According to a further exemplary embodiment of the present disclosure, atransmission is provided. The transmission comprising at least onestationary member; an input member; a plurality of planetary gearsetsoperatively coupled to the input member; a plurality of selectivecouplers operatively coupled to the plurality of planetary gearsets; andan output member operatively coupled to the input member through theplurality of planetary gearsets. Each planetary gearset of the pluralityof planetary gearsets includes a sun gear, a plurality of planet gearsoperatively coupled to the sun gear, a planet carrier operativelycoupled to the plurality of planet gears, and a ring gear operativelycoupled to the plurality of planet gears. The plurality of planetarygearsets including a first planetary gearset, a second planetarygearset, a third planetary gearset, and a fourth planetary gearset. Eachof the plurality of selective couplers has an engaged configuration anda disengaged configuration. The plurality of selective couplers includesa first number of clutches and a second number of brakes. The outputmember and the input member are both fixedly coupled to a first one ofthe first planetary gearset, the second planetary gearset, the thirdplanetary gearset, and the fourth planetary gearset. The input member isfixedly coupled to the plurality of planetary gearsets through a firstsun gear of the plurality of planetary gearsets and through a second sungear of the plurality of planetary gearsets. The output member isfurther fixedly coupled to a second one of the plurality of planetarygearsets.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of thisdisclosure, and the manner of attaining them, will become more apparentand will be better understood by reference to the following descriptionof exemplary embodiments taken in conjunction with the accompanyingdrawings, wherein:

FIG. 1 is a diagrammatic view of an exemplary multi-speed transmissionincluding four planetary gearsets and six selective couplers;

FIG. 2 is a truth table illustrating the selective engagement of the sixselective couplers of FIG. 1 to provide ten forward gear or speed ratiosand a reverse gear or speed ratio of the multi-speed transmission ofFIG. 1;

FIG. 3 is a diagrammatic view of another exemplary multi-speedtransmission including four planetary gearsets and six selectivecouplers; and

FIG. 4 is a truth table illustrating the selective engagement of the sixselective couplers of FIG. 3 to provide nine forward gear or speedratios and a reverse gear or speed ratio of the multi-speed transmissionof FIG. 3.

Corresponding reference characters indicate corresponding partsthroughout the several views. The exemplifications set out hereinillustrate exemplary embodiments of the invention and suchexemplifications are not to be construed as limiting the scope of theinvention in any manner.

DETAILED DESCRIPTION

For the purposes of promoting an understanding of the principles of thepresent disclosure, reference is now made to the embodiments illustratedin the drawings, which are described below. The embodiments disclosedbelow are not intended to be exhaustive or limit the present disclosureto the precise form disclosed in the following detailed description.Rather, the embodiments are chosen and described so that others skilledin the art may utilize their teachings. Therefore, no limitation of thescope of the present disclosure is thereby intended. Correspondingreference characters indicate corresponding parts throughout the severalviews.

In the disclosed transmission embodiments, selective couplers aredisclosed. A selective coupler is a device which may be actuated tofixedly couple two or more components together. A selective couplerfixedly couples two or more components to rotate together as a unit whenthe selective coupler is in an engaged configuration. Further, the twoor more components may be rotatable relative to each other when theselective coupler is in a disengaged configuration. The terms “couples”,“coupled”, “coupler” and variations thereof are used to include botharrangements wherein the two or more components are in direct physicalcontact and arrangements wherein the two or more components are not indirect contact with each other (e.g., the components are “coupled” viaat least a third component), but yet still cooperate or interact witheach other.

A first exemplary selective coupler is a clutch. A clutch couples two ormore rotating components to one another so that the two or more rotatingcomponents rotate together as a unit in an engaged configuration andpermits relative rotation between the two or more rotating components inthe disengaged position. Exemplary clutches may be shiftablefriction-locked multi-disk clutches, shiftable form-locking claw orconical clutches, wet clutches, or any other known form of a clutch.

A second exemplary selective coupler is a brake. A brake couples one ormore rotatable components to a stationary component to hold the one ormore rotatable components stationary relative to the stationarycomponent in the engaged configuration and permits rotation of the oneor more components relative to the stationary component in thedisengaged configuration. Exemplary brakes may be configured asshiftable-friction-locked disk brakes, shiftable friction-locked bandbrakes, shiftable form-locking claw or conical brakes, or any otherknown form of a brake.

Selective couplers may be actively controlled devices or passivedevices. Exemplary actively controlled devices include hydraulicallyactuated clutch or brake elements and electrically actuated clutch orbrake elements. Additional details regarding systems and methods forcontrolling selective couplers are disclosed in the above-incorporatedUS Published Patent Application No. 2016/0047440.

In addition to coupling through selective couplers, various componentsof the disclosed transmission embodiments may be fixedly coupledtogether continuously throughout the operation of the disclosedtransmissions. Components may be fixedly coupled together eitherpermanently or removably. Components may be fixedly coupled togetherthrough spline connections, press fitting, fasteners, welding, machinedor formed functional portions of a unitary piece, or other suitablemethods of connecting components.

The disclosed transmission embodiments include a plurality of planetarygearsets. Each planetary gearset includes at least four components: asun gear; a ring gear; a plurality of planet gears; and a carrier thatis rotatably coupled to and carries the planet gears. In the case of asimple planetary gearset, the teeth of the sun gear are intermeshed withthe teeth of the planet gears which are in turn intermeshed with theteeth of the ring gear. Each of these components may also be referred toas a gearset component. It will be apparent to one of skill in the artthat some planetary gearsets may include further components than thoseexplicitly identified. For example, one or more of the planetarygearsets may include two sets of planet gears. A first set of planetgears may intermesh with the sun gear while the second set of planetgears intermesh with the first set of planet gears and the ring gear.Both sets of planet gears are carried by the planet carrier.

One or more rotating components, such as shafts, drums, and othercomponents, may be collectively referred to as an interconnector whenthe one or more components are fixedly coupled together. Interconnectorsmay further be fixedly coupled to one or more gearset components and/orone or more selective couplers.

An input member of the disclosed transmission embodiments is rotated bya prime mover. Exemplary prime movers include internal combustionengines, electric motors, hybrid power systems, and other suitable powersystems. In one embodiment, the prime mover indirectly rotates the inputmember through a clutch and/or a torque converter. An output member ofthe disclosed transmission embodiments provides rotational power to oneor more working components. Exemplary working components include one ormore drive wheels of a motor vehicle, a power take-off shaft, and othersuitable devices. The output member is rotated based on theinterconnections of the gearset components and the selective couplers ofthe transmission. By changing the interconnections of the gearsetcomponents and the selective couplers, a rotation speed of the outputmember may be varied from a rotation speed of the input member.

The disclosed transmission embodiments are capable of transferringtorque from the input member to the output member and rotating theoutput member in at least nine forward gear or speed ratios relative tothe input member and at least one reverse gear or speed ratio whereinthe rotation direction of the output member is reversed relative to itsrotation direction for the at least nine forward ratios. Exemplary gearratios that may be obtained using the embodiments of the presentdisclosure are disclosed herein. Of course, other gear ratios areachievable depending on the characteristics of the gearsets utilized.Exemplary characteristics include respective gear diameters, the numberof gear teeth, and the configurations of the various gears.

FIG. 1 is a diagrammatic representation of a multi-speed transmission100. Multi-speed transmission 100 includes an input member 102 and anoutput member 104. Each of input member 102 and output member 104 isrotatable relative to at least one stationary member 106. An exemplaryinput member 102 is an input shaft or other suitable rotatablecomponent. An exemplary output member 104 is an output shaft or othersuitable rotatable component. An exemplary stationary member 106 is ahousing of multi-speed transmission 100. The housing may include severalcomponents coupled together.

Multi-speed transmission 100 includes a plurality of planetary gearsets,illustratively a first planetary gearset 108, a second planetary gearset110, a third planetary gearset 112, and a fourth planetary gearset 114.In one embodiment, additional planetary gearsets may be included.Further, although first planetary gearset 108, second planetary gearset110, third planetary gearset 112, and fourth planetary gearset 114 areillustrated as simple planetary gearsets, it is contemplated thatcompound planetary gearsets may be included in some embodiments.

In one embodiment, multi-speed transmission 100 is arranged asillustrated in FIG. 1, with first planetary gearset 108 positionedbetween a first location or end 116 at which input member 102 entersstationary member 106 and second planetary gearset 110, second planetarygearset 110 is positioned between first planetary gearset 108 and thirdplanetary gearset 112, third planetary gearset 112 is positioned betweensecond planetary gearset 110 and fourth planetary gearset 114, andfourth planetary gearset 114 is positioned between third planetarygearset 112 and a second location or end 118 at which output member 104exits stationary member 106. In alternative embodiments, first planetarygearset 108, second planetary gearset 110, third planetary gearset 112,and fourth planetary gearset 114 are arranged in any order relative tolocation 116 and location 118. In the illustrated embodiment of FIG. 1,each of first planetary gearset 108, second planetary gearset 110, thirdplanetary gearset 112, and fourth planetary gearset 114 are axiallyaligned. In one example, input member 102 and output member 104 are alsoaxially aligned with first planetary gearset 108, second planetarygearset 110, third planetary gearset 112, and fourth planetary gearset114. In alternative embodiments, one or more of input member 102, outputmember 104, first planetary gearset 108, second planetary gearset 110,third planetary gearset 112, and fourth planetary gearset 114 are offsetand not axially aligned with the remainder.

First planetary gearset 108 includes a sun gear 120, a planet carrier122 supporting a plurality of planet gears 124, and a ring gear 126.Second planetary gearset 110 includes a sun gear 130, a planet carrier132 supporting a plurality of planet gears 134, and a ring gear 136.Third planetary gearset 112 includes a sun gear 140, a planet carrier142 supporting a plurality of planet gears 144, and a ring gear 146.Fourth planetary gearset 114 includes a sun gear 150, a planet carrier152 supporting a plurality of planet gears 154, and a ring gear 156.

Multi-speed transmission 100 further includes a plurality of selectivecouplers, illustratively a first selective coupler 162, a secondselective coupler 164, a third selective coupler 166, a fourth selectivecoupler 168, a fifth selective coupler 170, and a sixth selectivecoupler 172. In the illustrated embodiment, first selective coupler 162and second selective coupler 164 are brakes and third selective coupler166, fourth selective coupler 168, fifth selective coupler 170, andsixth selective coupler 172 are clutches. The axial locations of theclutches and brakes relative to the plurality of planetary gearsets maybe altered from the illustrated axial locations.

Multi-speed transmission 100 includes several components that areillustratively shown as being fixedly coupled together. Input member 102is fixedly coupled to sun gear 120 of first planetary gearset 108, sungear 150 of fourth planetary gearset 114, and third selective coupler166. Output member 104 is fixedly coupled to planet carrier 152 offourth planetary gearset 114 and ring gear 146 of third planetarygearset 112. Ring gear 126 of first planetary gearset 108 and planetcarrier 132 of second planetary gearset 110 are fixedly coupledtogether. Ring gear 136 of second planetary gearset 110, sun gear 140 ofthird planetary gearset 112, and fourth selective coupler 168 arefixedly coupled together. Ring gear 156 of fourth planetary gearset 114is fixedly coupled to fifth selective coupler 170. Planet carrier 122 offirst planetary gearset 108, first selective coupler 162, and fourthselective coupler 168 are fixedly coupled together. Planet carrier 142of third planetary gearset 112, third selective coupler 166, fifthselective coupler 170, and sixth selective coupler 172 are fixedlycoupled together. Sun gear 130 of second planetary gearset 110, secondselective coupler 164, and sixth selective coupler 172 are fixedlycoupled together.

Multi-speed transmission 100 may be described as having eightinterconnectors. Input member 102 is a first interconnector that bothprovides input torque to multi-speed transmission 100 and fixedlycouples sun gear 120 of first planetary gearset 108, sun gear 150 offourth planetary gearset 114, and third selective coupler 166 together.Output member 104 is a second interconnector that both provides outputtorque from multi-speed transmission 100 and fixedly couples ring gear146 of third planetary gearset 112 to planet carrier 152 of fourthplanetary gearset 114. A third interconnector 180 fixedly couples ringgear 126 of first planetary gearset 108 and planet carrier 132 of secondplanetary gearset 110 together. A fourth interconnector 182 fixedlycouples ring gear 136 of second planetary gearset 110, sun gear 140 ofthird planetary gearset 112, and fourth selective coupler 168 together.A fifth interconnector 184 fixedly couples ring gear 156 of fourthplanetary gearset 114 to fifth selective coupler 170. A sixthinterconnector 186 fixedly couples planet carrier 122 of first planetarygearset 108, first selective coupler 162, and fourth selective coupler168 together. A seventh interconnector 188 fixedly couples planetcarrier 142 of third planetary gearset 112, third selective coupler 166,fifth selective coupler 170, and sixth selective coupler 172 together.An eighth interconnector 190 fixedly couples sun gear 130 of secondplanetary gearset 110, second selective coupler 164, and sixth selectivecoupler 172 together.

In one embodiment, first planetary gearset 108 and second planetarygearset 110 are a first subset of first planetary gearset 108, secondplanetary gearset 110, third planetary gearset 112, and fourth planetarygearset 114 and third planetary gearset 112 and fourth planetary gearset114 are a second subset of first planetary gearset 108, second planetarygearset 110, third planetary gearset 112, and fourth planetary gearset114. Fourth interconnector 182 fixedly couples the first subset of firstplanetary gearset 108, second planetary gearset 110, third planetarygearset 112, and fourth planetary gearset 114 to the second subset offirst planetary gearset 108, second planetary gearset 110, thirdplanetary gearset 112, and fourth planetary gearset 114. In theillustrated embodiment of transmission 100, fourth interconnector 182fixedly couples ring gear 136 of second planetary gearset 110 to sungear 140 of third planetary gearset 112. In other embodiments, fourthinterconnector 182 fixedly couples any one or more of the gearsetcomponents of the first subset of first planetary gearset 108, secondplanetary gearset 110, third planetary gearset 112, and fourth planetarygearset 114 to any one or more of the gearset components of the secondsubset of first planetary gearset 108, second planetary gearset 110,third planetary gearset 112, and fourth planetary gearset 114.

Multi-speed transmission 100 further includes several components thatare illustratively shown as being selectively coupled together throughselective couplers. First selective coupler 162, when engaged, fixedlycouples planet carrier 122 of first planetary gearset 108 to stationarymember 106. When first selective coupler 162 is disengaged, planetcarrier 122 of first planetary gearset 108 may rotate relative tostationary member 106.

Second selective coupler 164, when engaged, fixedly couples sun gear 130of second planetary gearset 110 to stationary member 106. When secondselective coupler 164 is disengaged, sun gear 130 of second planetarygearset 110 may rotate relative to stationary member 106.

Third selective coupler 166, when engaged, fixedly couples planetcarrier 142 of third planetary gearset 112 to sun gear 120 of firstplanetary gearset 108 and sun gear 150 of fourth planetary gearset 114.When third selective coupler 166 is disengaged, planet carrier 142 ofthird planetary gearset 112 may rotate relative to sun gear 120 of firstplanetary gearset 108 and sun gear 150 of fourth planetary gearset 114.

Fourth selective coupler 168, when engaged, fixedly couples planetcarrier 122 of first planetary gearset 108 to ring gear 136 of secondplanetary gearset 110 and sun gear 140 of third planetary gearset 112.When fourth selective coupler 168 is disengaged, planet carrier 122 offirst planetary gearset 108 may rotate relative to ring gear 136 ofsecond planetary gearset 110 and sun gear 140 of third planetary gearset112.

Fifth selective coupler 170, when engaged, fixedly couples ring gear 156of fourth planetary gearset 114 to planet carrier 142 of third planetarygearset 112. When fifth selective coupler 170 is disengaged, ring gear156 of fourth planetary gearset 114 may rotate relative to planetcarrier 142 of third planetary gearset 112.

Sixth selective coupler 172, when engaged, fixedly couples planetcarrier 142 of third planetary gearset 112 to sun gear 130 of secondplanetary gearset 110. When sixth selective coupler 172 is disengaged,planet carrier 142 of third planetary gearset 112 may rotate relative tosun gear 130 of second planetary gearset 110.

By engaging various combinations of first selective coupler 162, secondselective coupler 164, third selective coupler 166, fourth selectivecoupler 168, fifth selective coupler 170, and sixth selective coupler172, additional components of multi-speed transmission 100 may befixedly coupled together.

The plurality of planetary gearsets and the plurality of selectivecouplers of multi-speed transmission 100 may be interconnected invarious arrangements to provide torque from input member 102 to outputmember 104 in at least nine forward gear or speed ratios and one reversegear or speed ratio. Referring to FIG. 2, an exemplary truth table 200is shown that provides the state of each of first selective coupler 162,second selective coupler 164, third selective coupler 166, fourthselective coupler 168, fifth selective coupler 170, and sixth selectivecoupler 172 for ten different forward gear or speed ratios and onereverse gear or speed ratio. Each row corresponds to a giveninterconnection arrangement for transmission 100. The first columnprovides the gear range (reverse and 1^(st)-10^(th) forward gears). Thesecond column provides the gear ratio between the input member 102 andthe output member 104. The third column provides the gear step. The sixrightmost columns illustrate which ones of the selective couplers162-172 are engaged (“1” indicates engaged) and which ones of selectivecouplers 162-172 are disengaged (“(blank)” indicates disengaged). FIG. 2is only one example of any number of truth tables possible for achievingat least nine forward ratios and one reverse ratio.

In the example of FIG. 2, the illustrated reverse ratio (Rev) isachieved by having second selective coupler 164, fourth selectivecoupler 168, and sixth selective coupler 172 in an engaged configurationand first selective coupler 162, third selective coupler 166, and fifthselective coupler 170 in a disengaged configuration.

In one embodiment, to place multi-speed transmission 100 in neutral(Neu), all of first selective coupler 162, second selective coupler 164,third selective coupler 166, fourth selective coupler 168, fifthselective coupler 170, and sixth selective coupler 172 are in thedisengaged configuration. One or more of first selective coupler 162,second selective coupler 164, third selective coupler 166, fourthselective coupler 168, fifth selective coupler 170, and sixth selectivecoupler 172 may remain engaged in neutral (Neu) as long as thecombination of first selective coupler 162, second selective coupler164, third selective coupler 166, fourth selective coupler 168, fifthselective coupler 170, and sixth selective coupler 172 does not transmittorque from input member 102 to output member 104.

A first forward ratio (shown as 1st) in truth table 200 of FIG. 2 isachieved by having first selective coupler 162, second selective coupler164, and sixth selective coupler 172 in an engaged configuration andthird selective coupler 166, fourth selective coupler 168, and fifthselective coupler 170 in a disengaged configuration.

A second or subsequent forward ratio (shown as 2nd) in truth table 200of FIG. 2 is achieved by having second selective coupler 164, fifthselective coupler 170, and sixth selective coupler 172 in an engagedconfiguration and first selective coupler 162, third selective coupler166, and fourth selective coupler 168 in a disengaged configuration.Therefore, when transitioning between the first forward ratio and thesecond forward ratio, first selective coupler 162 is placed in thedisengaged configuration and fifth selective coupler 170 is placed inthe engaged configuration.

A third or subsequent forward ratio (shown as 3rd) in truth table 200 ofFIG. 2 is achieved by having first selective coupler 162, secondselective coupler 164, and fifth selective coupler 170 in an engagedconfiguration and third selective coupler 166, fourth selective coupler168, and sixth selective coupler 172 in a disengaged configuration.Therefore, when transitioning between the second forward ratio and thethird forward ratio, sixth selective coupler 172 is placed in thedisengaged configuration and first selective coupler 162 is placed inthe engaged configuration.

A fourth or subsequent forward ratio (shown as 4th) in truth table 200of FIG. 2 is achieved by having first selective coupler 162, fourthselective coupler 168, and fifth selective coupler 170 in an engagedconfiguration and second selective coupler 164, third selective coupler166, and sixth selective coupler 172 in a disengaged configuration.Therefore, when transitioning between the third forward ratio and thefourth forward ratio, second selective coupler 164 is placed in thedisengaged configuration and fourth selective coupler 168 is placed inthe engaged configuration.

A fifth or subsequent forward ratio (shown as 5th) in truth table 200 ofFIG. 2 is achieved by having second selective coupler 164, fourthselective coupler 168, and fifth selective coupler 170 in an engagedconfiguration and first selective coupler 162, third selective coupler166, and sixth selective coupler 172 in a disengaged configuration.Therefore, when transitioning between the fourth forward ratio and thefifth forward ratio, first selective coupler 162 is placed in thedisengaged configuration and second selective coupler 164 is placed inthe engaged configuration.

A sixth or subsequent forward ratio (shown as 6th) in truth table 200 ofFIG. 2 is achieved by having second selective coupler 164, thirdselective coupler 166, and fifth selective coupler 170 in an engagedconfiguration and first selective coupler 162, fourth selective coupler168, and sixth selective coupler 172 in a disengaged configuration.Therefore, when transitioning between the fifth forward ratio and thesixth forward ratio, fourth selective coupler 168 is placed in thedisengaged configuration and third selective coupler 166 is placed inthe engaged configuration. In the sixth forward ratio, torque is carriedonly by third selective coupler 166 and fifth selective coupler 170,thus second selective coupler 164 does not need to be engaged.

A seventh or subsequent forward ratio (shown as 7th) in truth table 200of FIG. 2 is achieved by having second selective coupler 164, thirdselective coupler 166, and fourth selective coupler 168 in an engagedconfiguration and first selective coupler 162, fifth selective coupler170, and sixth selective coupler 172 in a disengaged configuration.Therefore, when transitioning between the sixth forward ratio and theseventh forward ratio, fifth selective coupler 170 is placed in thedisengaged configuration and fourth selective coupler 168 is placed inthe engaged configuration.

An eighth or subsequent forward ratio (shown as 8th) in truth table 200of FIG. 2 is achieved by having first selective coupler 162, thirdselective coupler 166, and fourth selective coupler 168 in an engagedconfiguration and second selective coupler 164, fifth selective coupler170, and sixth selective coupler 172 in a disengaged configuration.Therefore, when transitioning between the seventh forward ratio and theeighth forward ratio, second selective coupler 164 is placed in thedisengaged configuration and first selective coupler 162 is placed inthe engaged configuration.

A ninth or subsequent forward ratio (shown as 9th) in truth table 200 ofFIG. 2 is achieved by having first selective coupler 162, secondselective coupler 164, and third selective coupler 166 in an engagedconfiguration and fourth selective coupler 168, fifth selective coupler170, and sixth selective coupler 172 in a disengaged configuration.Therefore, when transitioning between the eighth forward ratio and theninth forward ratio, fourth selective coupler 168 is placed in thedisengaged configuration and second selective coupler 164 is placed inthe engaged configuration.

A tenth or subsequent forward ratio (shown as 10th) in truth table 200of FIG. 2 is achieved by having first selective coupler 162, thirdselective coupler 166, and sixth selective coupler 172 in an engagedconfiguration and second selective coupler 164, fourth selective coupler168, and fifth selective coupler 170 in a disengaged configuration.Therefore, when transitioning between the ninth forward ratio and thetenth forward ratio, second selective coupler 164 is placed in thedisengaged configuration and sixth selective coupler 172 is placed inthe engaged configuration.

The present disclosure contemplates that downshifts follow the reversesequence of the corresponding upshift (as described above). Further,several power-on skip-shifts that are single-transition are possible(e.g. from 1^(st) up to 3^(rd), from 3^(rd) down to 1^(st), from 3^(rd)up to 5^(th), and from 5^(th) down to 3^(rd)).

FIG. 3 is a diagrammatic representation of a multi-speed transmission300. Multi-speed transmission 300 includes an input member 302 and anoutput member 304. Each of input member 302 and output member 304 isrotatable relative to at least one stationary member 306. An exemplaryinput member 302 is an input shaft or other suitable rotatablecomponent. An exemplary output member 304 is an output shaft or othersuitable rotatable component. An exemplary stationary member 306 is ahousing of multi-speed transmission 300. The housing may include severalcomponents coupled together.

Multi-speed transmission 300 includes a plurality of planetary gearsets,illustratively a first planetary gearset 308, a second planetary gearset310, a third planetary gearset 312, and a fourth planetary gearset 314.In one embodiment, additional planetary gearsets may be included.Further, although first planetary gearset 308, second planetary gearset310, third planetary gearset 312, and fourth planetary gearset 314 areillustrated as simple planetary gearsets, it is contemplated thatcompound planetary gearsets may be included in some embodiments.

In one embodiment, multi-speed transmission 300 is arranged asillustrated in FIG. 3, with first planetary gearset 308 positionedbetween a first location or end 316 at which input member 302 entersstationary member 306 and second planetary gearset 310, second planetarygearset 310 is positioned between first planetary gearset 308 and thirdplanetary gearset 312, third planetary gearset 312 is positioned betweensecond planetary gearset 310 and fourth planetary gearset 314, andfourth planetary gearset 314 is positioned between third planetarygearset 312 and a second location or end 318 at which output member 304exits stationary member 306. In alternative embodiments, first planetarygearset 308, second planetary gearset 310, third planetary gearset 312,and fourth planetary gearset 314 are arranged in any order relative tolocation 316 and location 318. In the illustrated embodiment of FIG. 3,each of first planetary gearset 308, second planetary gearset 310, thirdplanetary gearset 312, and fourth planetary gearset 314 are axiallyaligned. In one example, input member 302 and output member 304 are alsoaxially aligned with first planetary gearset 308, second planetarygearset 310, third planetary gearset 312, and fourth planetary gearset314. In alternative embodiments, one or more of input member 302, outputmember 304, first planetary gearset 308, second planetary gearset 310,third planetary gearset 312, and fourth planetary gearset 314 are offsetand not axially aligned with the remainder.

First planetary gearset 308 includes a sun gear 320, a planet carrier322 supporting a plurality of planet gears 324, and a ring gear 326.Second planetary gearset 310 includes a sun gear 330, a planet carrier332 supporting a plurality of planet gears 334, and a ring gear 336.Third planetary gearset 312 includes a sun gear 340, a planet carrier342 supporting a plurality of planet gears 344, and a ring gear 346.Fourth planetary gearset 314 includes a sun gear 350, a planet carrier352 supporting a plurality of planet gears 354, and a ring gear 356.

Multi-speed transmission 300 further includes a plurality of selectivecouplers, illustratively a first selective coupler 362, a secondselective coupler 364, a third selective coupler 366, a fourth selectivecoupler 368, a fifth selective coupler 370, and a sixth selectivecoupler 372. In the illustrated embodiment, first selective coupler 362,second selective coupler 364, and sixth selective coupler 372 are brakesand third selective coupler 366, fourth selective coupler 368, and fifthselective coupler 370 are clutches. The axial locations of the clutchesand brakes relative to the plurality of planetary gearsets may bealtered from the illustrated axial locations.

Multi-speed transmission 300 includes several components that areillustratively shown as being fixedly coupled together. Input member 302is fixedly coupled to sun gear 320 of first planetary gearset 308, sungear 350 of fourth planetary gearset 114, and third selective coupler366. Output member 304 is fixedly coupled to planet carrier 352 offourth planetary gearset 314 and ring gear 346 of third planetarygearset 312. Ring gear 326 of first planetary gearset 308 and planetcarrier 332 of second planetary gearset 310 are fixedly coupledtogether. Ring gear 336 of second planetary gearset 310, sun gear 340 ofthird planetary gearset 312, and fourth selective coupler 368 arefixedly coupled together. Ring gear 356 of fourth planetary gearset 314is fixedly coupled to fifth selective coupler 370. Planet carrier 322 offirst planetary gearset 308, fourth selective coupler 368, and firstselective coupler 362 are fixedly coupled together. Planet carrier 342of third planetary gearset 312, third selective coupler 366, fifthselective coupler 370, and sixth selective coupler 372 are fixedlycoupled together. Sun gear 330 of second planetary gearset 310 isfixedly coupled to second selective coupler 364.

Multi-speed transmission 300 may be described as having eightinterconnectors. Input member 302 is a first interconnector that bothprovides input torque to multi-speed transmission 300 and fixedlycouples sun gear 320 of first planetary gearset 308, sun gear 350 offourth planetary gearset 314, and third selective coupler 366 together.Output member 304 is a second interconnector that both provides outputtorque from multi-speed transmission 300 and fixedly couples planetcarrier 352 of fourth planetary gearset 314 to ring gear 346 of thirdplanetary gearset 312. A third interconnector 380 fixedly couples ringgear 326 of first planetary gearset 308, and planet carrier 332 ofsecond planetary gearset 310 together. A fourth interconnector 382fixedly couples ring gear 336 of second planetary gearset 310, sun gear340 of third planetary gearset 312, and fourth selective coupler 368together. A fifth interconnector 384 fixedly couples ring gear 356 offourth planetary gearset 314 to fifth selective coupler 370. A sixthinterconnector 386 fixedly couples planet carrier 322 of first planetarygearset 308, first selective coupler 362, and fourth selective coupler368 together. A seventh interconnector 388 fixedly couples planetcarrier 342 of third planetary gearset 312, third selective coupler 366,fifth selective coupler 370, and sixth selective coupler 372. An eighthinterconnector 390 fixedly couples sun gear 330 of second planetarygearset 310 to second selective coupler 364.

In one embodiment, first planetary gearset 308 and second planetarygearset 310 are a first subset of first planetary gearset 308, secondplanetary gearset 310, third planetary gearset 312, and fourth planetarygearset 314 and third planetary gearset 312 and fourth planetary gearset314 are a second subset of first planetary gearset 308, second planetarygearset 310, third planetary gearset 312, and fourth planetary gearset314. Fourth interconnector 382 fixedly couples the first subset of firstplanetary gearset 308, second planetary gearset 310, third planetarygearset 312, and fourth planetary gearset 314 to the second subset offirst planetary gearset 308, second planetary gearset 310, thirdplanetary gearset 312, and fourth planetary gearset 314. In theillustrated embodiment of transmission 300, fourth interconnector 382fixedly couples ring gear 336 of second planetary gearset 310 to sungear 340 of third planetary gearset 312. In other embodiments, fourthinterconnector 382 fixedly couples any one or more of the gearsetcomponents of the first subset of first planetary gearset 308, secondplanetary gearset 310, third planetary gearset 312, and fourth planetarygearset 314 to any one or more of the gearset components of the secondsubset of first planetary gearset 308, second planetary gearset 310,third planetary gearset 312, and fourth planetary gearset 314.

Multi-speed transmission 300 further includes several components thatare illustratively shown as being selectively coupled together throughselective couplers. First selective coupler 362, when engaged, fixedlycouples planet carrier 322 of first planetary gearset 308 to stationarymember 306. When first selective coupler 362 is disengaged, planetcarrier 322 of first planetary gearset 308 may rotate relative tostationary member 306.

Second selective coupler 364, when engaged, fixedly couples sun gear 330of second planetary gearset 310 to stationary member 306. When secondselective coupler 364 is disengaged, sun gear 330 of second planetarygearset 310 may rotate relative to stationary member 306.

Third selective coupler 366, when engaged, fixedly couples planetcarrier 342 of third planetary gearset 312 to sun gear 320 of firstplanetary gearset 308 and sun gear 350 of fourth planetary gearset 314.When third selective coupler 366 is disengaged, planet carrier 342 ofthird planetary gearset 312 may rotate relative to sun gear 320 of firstplanetary gearset 308 and sun gear 350 of fourth planetary gearset 314.

Fourth selective coupler 368, when engaged, fixedly couples planetcarrier 322 of first planetary gearset 308 to ring gear 336 of secondplanetary gearset 310 and sun gear 340 of third planetary gearset 312.When fourth selective coupler 368 is disengaged, planet carrier 322 offirst planetary gearset 308 may rotate relative to ring gear 336 ofsecond planetary gearset 310 and sun gear 340 of third planetary gearset312.

Fifth selective coupler 370, when engaged, fixedly couples ring gear 356of fourth planetary gearset 314 to planet carrier 342 of third planetarygearset 312. When fifth selective coupler 370 is disengaged, ring gear356 of fourth planetary gearset 314 may rotate relative to planetcarrier 342 of third planetary gearset 312.

Sixth selective coupler 372, when engaged, fixedly couples planetcarrier 342 of third planetary gearset 312 to stationary member 306.When sixth selective coupler 372 is disengaged, planet carrier 342 ofthird planetary gearset 312 may rotate relative to stationary member306.

By engaging various combinations of first selective coupler 362, secondselective coupler 364, third selective coupler 366, fourth selectivecoupler 368, fifth selective coupler 370, and sixth selective coupler372, additional components of multi-speed transmission 300 may befixedly coupled together.

The plurality of planetary gearsets and the plurality of selectivecouplers of multi-speed transmission 300 may be interconnected invarious arrangements to provide torque from input member 302 to outputmember 304 in at least nine forward gear or speed ratios and one reversegear or speed ratio. Referring to FIG. 4, an exemplary truth table 400is shown that provides the state of each of first selective coupler 362,second selective coupler 364, third selective coupler 366, fourthselective coupler 368, fifth selective coupler 370, and sixth selectivecoupler 372 for nine different forward gear or speed ratios and onereverse gear or speed ratio. Each row corresponds to a giveninterconnection arrangement for transmission 300. The first columnprovides the gear range (reverse and 1^(st)-9^(th) forward gears). Thesecond column provides the gear ratio between the input member 302 andthe output member 304. The third column provides the gear step. The sixrightmost columns illustrate which ones of the selective couplers362-372 are engaged (“1” indicates engaged) and which ones of selectivecouplers 362-372 are disengaged (“(blank)” indicates disengaged). FIG. 4is only one example of any number of truth tables possible for achievingat least nine forward ratios and one reverse ratio.

In the example of FIG. 4, the illustrated reverse ratio (Rev) isachieved by having second selective coupler 364, fourth selectivecoupler 368, and sixth selective coupler 372 in an engaged configurationand first selective coupler 362, third selective coupler 366, and fifthselective coupler 370 in a disengaged configuration.

In one embodiment, to place multi-speed transmission 300 in neutral(Neu), all of first selective coupler 362, second selective coupler 364,third selective coupler 366, fourth selective coupler 368, fifthselective coupler 370, and sixth selective coupler 372 are in thedisengaged configuration. One or more of first selective coupler 362,second selective coupler 364, third selective coupler 366, fourthselective coupler 368, fifth selective coupler 370, and sixth selectivecoupler 372 may remain engaged in neutral (Neu) as long as thecombination of first selective coupler 362, second selective coupler364, third selective coupler 366, fourth selective coupler 368, fifthselective coupler 370, and sixth selective coupler 372 does not transmittorque from input member 302 to output member 304.

A first forward ratio (shown as 1st) in truth table 400 of FIG. 4 isachieved by having first selective coupler 362, second selective coupler364, and sixth selective coupler 372 in an engaged configuration andthird selective coupler 366, fourth selective coupler 368, and fifthselective coupler 370 in a disengaged configuration.

A second or subsequent forward ratio (shown as 2nd) in truth table 400of FIG. 4 is achieved by having second selective coupler 364, fifthselective coupler 370, and sixth selective coupler 372 in an engagedconfiguration and first selective coupler 362, third selective coupler366, and fourth selective coupler 368 in a disengaged configuration.Therefore, when transitioning between the first forward ratio and thesecond forward ratio, first selective coupler 362 is placed in thedisengaged configuration and fifth selective coupler 370 is placed inthe engaged configuration.

A third or subsequent forward ratio (shown as 3rd) in truth table 400 ofFIG. 4 is achieved by having first selective coupler 362, secondselective coupler 364, and fifth selective coupler 370 in an engagedconfiguration and third selective coupler 366, fourth selective coupler368, and sixth selective coupler 372 in a disengaged configuration.Therefore, when transitioning between the second forward ratio and thethird forward ratio, sixth selective coupler 372 is placed in thedisengaged configuration and first selective coupler 362 is placed inthe engaged configuration.

A fourth or subsequent forward ratio (shown as 4th) in truth table 400of FIG. 4 is achieved by having first selective coupler 362, fourthselective coupler 368, and fifth selective coupler 370 in an engagedconfiguration and second selective coupler 364, third selective coupler366, and sixth selective coupler 372 in a disengaged configuration.Therefore, when transitioning between the third forward ratio and thefourth forward ratio, second selective coupler 364 is placed in thedisengaged configuration and fourth selective coupler 368 is placed inthe engaged configuration.

A fifth or subsequent forward ratio (shown as 5th) in truth table 400 ofFIG. 4 is achieved by having second selective coupler 364, fourthselective coupler 368, and fifth selective coupler 370 in an engagedconfiguration and first selective coupler 362, third selective coupler366, and sixth selective coupler 372 in a disengaged configuration.Therefore, when transitioning between the fourth forward ratio and thefifth forward ratio, first selective coupler 362 is placed in thedisengaged configuration and second selective coupler 364 is placed inthe engaged configuration.

A sixth or subsequent forward ratio (shown as 6th) in truth table 400 ofFIG. 4 is achieved by having second selective coupler 364, thirdselective coupler 366, and fifth selective coupler 370 in an engagedconfiguration and first selective coupler 362, fourth selective coupler368, and sixth selective coupler 372 in a disengaged configuration.Therefore, when transitioning between the fifth forward ratio and thesixth forward ratio, fourth selective coupler 368 is placed in thedisengaged configuration and third selective coupler 366 is placed inthe engaged configuration. In the sixth forward ratio, torque is carriedonly by third selective coupler 366 and fifth selective coupler 370,thus second selective coupler 364 does not need to be engaged.

A seventh or subsequent forward ratio (shown as 7th) in truth table 400of FIG. 4 is achieved by having second selective coupler 364, thirdselective coupler 366, and fourth selective coupler 368 in an engagedconfiguration and first selective coupler 362, fifth selective coupler370, and sixth selective coupler 372 in a disengaged configuration.Therefore, when transitioning between the sixth forward ratio and theseventh forward ratio, fifth selective coupler 370 is placed in thedisengaged configuration and fourth selective coupler 368 is placed inthe engaged configuration.

An eighth or subsequent forward ratio (shown as 8th) in truth table 400of FIG. 4 is achieved by having first selective coupler 362, thirdselective coupler 366, and fourth selective coupler 368 in an engagedconfiguration and second selective coupler 364, fifth selective coupler370, and sixth selective coupler 372 in a disengaged configuration.Therefore, when transitioning between the seventh forward ratio and theeighth forward ratio, second selective coupler 364 is placed in thedisengaged configuration and first selective coupler 362 is placed inthe engaged configuration.

A ninth or subsequent forward ratio (shown as 9th) in truth table 400 ofFIG. 4 is achieved by having first selective coupler 362, secondselective coupler 364, and third selective coupler 366 in an engagedconfiguration and fourth selective coupler 368, fifth selective coupler370, and sixth selective coupler 372 in a disengaged configuration.Therefore, when transitioning between the eighth forward ratio and theninth forward ratio, fourth selective coupler 368 is placed in thedisengaged configuration and second selective coupler 364 is placed inthe engaged configuration.

The present disclosure contemplates that downshifts follow the reversesequence of the corresponding upshift (as described above). Further,several power-on skip-shifts that are single-transition are possible(e.g. from 1^(st) up to 3^(rd), from 3^(rd) down to 1^(st), from 3^(rd)up to 5^(th), and from 5^(th) down to 3^(rd)).

In the illustrated embodiments, various combinations of three of theavailable selective couplers are engaged for each of the illustratedforward speed ratios and reverse speed ratios. Additional forward speedratios and reverse speed ratios are possible based on other combinationsof engaged selective couplers. Although in the illustrated embodiments,each forward speed ratio and reverse speed ratio has three of theavailable selective couplers engaged, it is contemplated that less thanthree and more than three selective couplers may be engaged at the sametime.

While this invention has been described as having exemplary designs, thepresent invention can be further modified within the spirit and scope ofthis disclosure. This application is therefore intended to cover anyvariations, uses, or adaptations of the invention using its generalprinciples. Further, this application is intended to cover suchdepartures from the present disclosure as come within known or customarypractice in the art to which this invention pertains and which fallwithin the limits of the appended claims.

What is claimed is:
 1. A transmission comprising: at least onestationary member; an input member; a plurality of planetary gearsetsoperatively coupled to the input member, each planetary gearset of theplurality of planetary gearsets including a sun gear, a plurality ofplanet gears operatively coupled to the sun gear, a planet carrieroperatively coupled to the plurality of planet gears, and a ring gearoperatively coupled to the plurality of planet gears, the plurality ofplanetary gearsets including a first planetary gearset, a secondplanetary gearset, a third planetary gearset, and a fourth planetarygearset; a plurality of selective couplers operatively coupled to theplurality of planetary gearsets, each of the plurality of selectivecouplers having an engaged configuration and a disengaged configuration,the plurality of selective couplers including a first number of clutchesand a second number of brakes; and an output member operatively coupledto the input member through the plurality of planetary gearsets, theoutput member and the input member are both fixedly coupled to a firstone of the first planetary gearset, the second planetary gearset, thethird planetary gearset, and the fourth planetary gearset, the inputmember is fixedly coupled to the plurality of planetary gearsets througha first sun gear of the plurality of planetary gearsets and through asecond sun gear of the plurality of planetary gearsets, and the outputmember is fixedly coupled to a second one of the plurality of planetarygearsets.
 2. The transmission of claim 1, wherein the first sun gear ofthe plurality of planetary gearsets is the sun gear of the firstplanetary gearset and the second sun gear of the plurality of planetarygearsets is the sun gear of the fourth planetary gearset and a sum ofthe first number of clutches and the second number of brakes is six. 3.The transmission of claim 2, wherein the plurality of selective couplersincludes a first clutch, a second clutch, a third clutch, a fourthclutch, a first brake fixedly coupled to the at least one stationarymember, and a second brake fixedly coupled to the at least onestationary member.
 4. The transmission of claim 3, wherein the firstclutch, when engaged, fixedly couples the planet carrier of the thirdplanetary gearset and the ring gear of the fourth planetary gearset tothe sun gear of the second planetary gearset.
 5. The transmission ofclaim 2, wherein the plurality of selective couplers includes a firstclutch, a second clutch, a third clutch, a first brake fixedly coupledto the at least one stationary member, a second brake fixedly coupled tothe at least one stationary member, and a third brake fixedly coupled tothe at least one stationary member.
 6. The transmission of claim 5,wherein the first brake, when engaged, fixedly couples the planetcarrier of the third planetary gearset to the at least one stationarymember.
 7. The transmission of claim 1, further comprising: a firstinterconnector which fixedly couples the ring gear of the firstplanetary gearset to the planet carrier of the second planetary gearset;and a second interconnector which fixedly couples the ring gear of thesecond planetary gearset to the sun gear of the third planetary gearset.8. The transmission of claim 7, further comprising: a first selectivecoupler which, when engaged, fixedly couples the planet carrier of thefirst planetary transmission to the at least one stationary member; asecond selective coupler which, when engaged, fixedly couples the ringgear of the second planetary gearset to the at least one stationarymember; a third selective coupler which, when engaged, fixedly couplesthe planet carrier of the third planetary gearset to the sun gear of thefirst planetary gearset and the sun gear of the fourth planetarygearset; a fourth selective coupler which, when engaged, fixedly couplesthe planet carrier of the first planetary gearset to the ring gear ofthe second planetary gearset and the sun gear of the third planetarygearset; and a fifth selective coupler which, when engaged, fixedlycouples the planet carrier of the third planetary gearset to the ringgear of the fourth planetary gearset.
 9. The transmission of claim 8,further comprising a sixth selective coupler which, when engaged,fixedly couples the sun gear of the second planetary gearset to theplanet carrier of the third planetary gearset.
 10. The transmission ofclaim 8, further comprising a sixth selective coupler which, whenengaged, fixedly couples the planet carrier of the third planetarygearset to the at least one stationary member.
 11. The transmission ofclaim 8, wherein the at least one stationary member includes a housing,the housing having a first end and a second end, wherein: the inputmember is accessible proximate the first end of the housing; the outputmember is accessible proximate the second end of the housing; the firstplanetary gearset is positioned between the first end of the housing andthe second planetary gearset; the second planetary gearset is positionedbetween the first planetary gearset and the third planetary gearset; thethird planetary gearset is positioned between the second planetarygearset and the fourth planetary gearset; and the fourth planetarygearset is positioned between the third planetary gearset and the secondend of the housing.
 12. The transmission of claim 11, wherein each ofthe first planetary gearset, the second planetary gearset, the thirdplanetary gearset, and the fourth planetary gearset is a simpleplanetary gearset.
 13. The transmission of claim 1, wherein theplurality of selective couplers are selectively engaged in a pluralityof combinations to establish at least nine forward speed ratios and atleast one reverse speed ratio between the input member and the outputmember, each of the plurality of combinations having at least three ofthe plurality of selective couplers engaged.
 14. The transmission ofclaim 13, wherein the plurality of selective couplers includes a firstbrake fixedly coupled to the at least one stationary member, a secondbrake fixedly coupled to the at least one stationary member, and a thirdbrake fixedly coupled to the at least one stationary member, each of thefirst brake, the second brake, and the third brake engaged in at leastone forward speed ratio of the at least nine forward speed ratios. 15.The transmission of claim 13, wherein the plurality of selectivecouplers includes at least a first brake fixedly coupled to the at leastone stationary member and a second brake fixedly coupled to the at leastone stationary member, only one of the first brake and the second brakeengaged in at least five forward speed ratios of the at least nineforward speed ratios.